The use of organic luminescent materials or phosphors is known in the art. WO/2008/130562, for instance, describes a composition comprising at least one organic and/or inorganic phosphor in a physiologically acceptable medium, wherein the phosphor(s) is present in an amount effective to convert electromagnetic radiation of an initial frequency to a different frequency. In one embodiment, the phosphors convert the initial radiation frequency, such as infrared or visible light, to a higher frequency, such as ultraviolet (UV) radiation. In another embodiment, the phosphors convert the initial radiation from a higher frequency, such as UV radiation, to a lower frequency, such as infrared or visible light.